While most of us have multi TB drives, it's still a bit "wrong" to see that the "minimalist" clients have +25 MB install kits while utorrent 2.2.1 is still rocking in 300 kb. Just saying...
baretorrent is not "small", it's simple. Most of its size comes from wxWidgets and python, which are there for the extensions. Linking statically to all the libraries and ditching python could probably reduce the size by an order of magnitude.